JPH0289964A - Compressor for Stirling cycle refrigeration equipment - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a compressor suitably applied to a Stirling cycle refrigeration system.

[Prior Art] A Stirling cycle refrigeration system is constructed by housing a compressor and an expander in an integrated casing.

These pistons and displacers are each connected to a common drive source via a crank mechanism, and are driven synchronously under a predetermined phase. At this time, for structural convenience, both are disposed at positions where strokes are perpendicular to each other.

In such a structure, He gas, which is a working fluid, is compressed by a piston and sent to the expander in a pressurized state. Here, the displacer is used to cause adiabatic expansion and cooling. The cooled He gas is sent back to the piston to be compressed again. This well-known gas cycle is then repeated, creating a cryogenic cold head at the end of the casing housing the displacer.

This cold head is sealed in a vacuum insulation container attached to a casing, and objects to be cooled, such as sensors, are suitably accommodated in this sealed space and used for the intended purpose.

[Problems to be Solved by the Invention] However, due to its characteristics, He gas, which is a working fluid, is very prone to leakage, and it is not easy to ensure a reliable seal between a piston and a cylinder in a compressor. For this reason, gas may escape through the sliding gap, resulting in a situation in which the required compression ratio cannot be obtained, which has been a serious problem in the past.

Therefore, in order to solve this problem, it has been considered as an effective means to configure the compressor with a diaphragm instead of a piston. This is because if a diaphragm is used, there is no sliding gap like that between a piston and a cylinder, so there is a possibility that the problem of gas leaks can be fundamentally solved.

However, a diaphragm requires a large diameter area to create the required compression volume. If the mounting position follows the existing Stirling system, the operating direction of the diaphragm will be perpendicular to the stroke direction of the displacer. Therefore, it is thought that if this method is adopted, the size of the refrigeration equipment will be excessively large, and therefore, the possibility of its use at present is low.

The present invention has been made in view of these problems, and provides a compressor for a Stirling cycle refrigeration system that suitably employs a diaphragm and fundamentally solves the problem of gas leakage without increasing the size of the compressor. The aim is to realize the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

That is, the compressor for a Stirling cycle refrigeration system of the present invention is applied to a Stirling cycle refrigeration system in which a cold head of a casing containing a displacer is sealed with a vacuum insulation container attached to the base of the casing. A diaphragm that operates in the same direction as the displacer is attached to the outer wall of the base, and an expandable and contractible space formed between the diaphragm and the outer wall of the base serves as a compression chamber.

[Function] As mentioned above, the vacuum insulated container is used to seal the cold head of the casing within a certain space, and is essential for refrigeration equipment in order to accommodate the object to be cooled and maintain a state of insulation from the outside. It is a component that cannot be used. Due to such operational and thermal insulation needs, a somewhat large diameter is generally required. Therefore, attaching the diaphragm to the base of this insulating container does not occupy a large amount of new space solely for the diaphragm. In principle, the entire refrigeration system only increases by a thickness that approximately corresponds to the working volume of the diaphragm. This eliminates the need for a piston structure, and as a result, there is a higher probability that the entire refrigeration system will be downsized. Moreover, since the operating direction of the diaphragm is made to match that of the displacer, it is possible to further facilitate structural consolidation.

Since the diaphragm is allowed to have a diameter corresponding to the base area, a compression chamber having the required volume can be relatively easily formed without ensuring a very large thickness. Therefore, even though this device is compact, it can have appropriate functions.

[Example code] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

A compressor 1 of this embodiment is integrally formed with a casing 3 together with an expander 2, thereby constructing a Stirling cycle refrigeration system as shown in FIG.

The casing 3 includes a base 31, a cylinder 32 projecting from the base 31, and a motor case 33 attached to the base outer wall 31a. The projecting end of the cylinder 32 serves as a cold head 32a, and the cold head 32a is hermetically sealed with a vacuum insulation container 4 whose lid is attached to the base 31. Inside the cylinder 32 is the motor case 3
It is connected to the inside of 3.

The expander 2 accommodates a displacer 21 in the cylinder 32 so as to be movable up and down, and defines a space A that expands and contracts between the upper end of the displacer 21 and the cold head 32a as an expansion chamber. On the other hand, inside the motor case 33, there is a permanent magnet 5 having a recess 51a in the center and disposed around it.
A movable bracket 51, which is a moving body of a linear motor and is biased upward and downward by a coil 54 and a movable bracket 51, is provided.

Further, a coil 53 is provided on the inner periphery of the recess 51a of the movable bracket 51, and the lower end of the displacer 21 is inserted into the inner periphery of the coil 53, thereby configuring a linear motor for driving the displacer 21 different from the above. and,
By appropriately energizing this coil 53, the displacer 21 can be moved up and down by electromagnetic force.

The compressor 1 includes a displacer 2 on the base outer wall 31a.
Attach a diaphragm 11 that has the same operating direction as 1,
An expandable and contractible space B formed between this diaphragm 11 and the base outer wall 31a is used as a compression chamber. That is, the diaphragm 11 is a thin donut-shaped flexible plate, and is set to have a diameter between the base 31 and the path. The outer peripheral edge 11a is fixed to the outer peripheral edge of the base outer wall 31a, and the inner peripheral edge 11b is attached to the top plate of the movable bracket 51. Thereby, the above-mentioned space B surrounded by the base outer wall 31a, the diaphragm 1, and the outer periphery of the displacer 21 functions as a compression chamber. Then, by appropriately energizing the coil 54, the movable bracket 5] is moved up and down by electromagnetic force, and the diaphragm 1
1 in the stroke direction of the displacer 21.

By the way, the displacer 21 has a regenerator 22 installed therein, and communication holes 23 are provided through the regenerator 22 and open to the outer periphery of the side and the upper end surface of the displacer 21, respectively. ing. The above-mentioned compression chamber B is communicated with the expansion chamber A through this communication hole 23. Further, as the displacer 21 moves, its lower end surface and the recess 51a of the movable bracket 51
A space C expanded and contracted between the bottom wall and the bottom wall is a gas reservoir chamber communicating with the compression chamber B. That is, these expansion chamber A, compression chamber B, and gas reservoir chamber C are always under equal pressure.

Note that a cooling water pipe 6 is buried above the base 31 and introduced by penetrating the inside of the vacuum insulation container 4, and plays the role of an aftercooler to cool the He gas immediately after being pressurized in the compression chamber B. .

Next, the operation of this embodiment will be explained. First, the displacer 21 is positioned at the top dead center. At this time, diaphragm 1
1 is kept in an engraved state containing He gas. Then, the movable bracket 51 is moved upward to press the diaphragm 11 and compress the He gas in the compression chamber B. At this time, H
The e-gas is cooled by a cooling water pipe 6. Next, only the displacer 21 is lowered to the intermediate position without operating the diaphragm 11, and the pressurized He gas is sent to the expansion chamber A through the cooler 22 while being cooled. Thereafter, the displacer 21 is moved downward together with the expansion operation of the diaphragm 11, and the He gas is adiabatically expanded and cooled in the expansion chamber A. Finally, only the displacer 21 is returned to its original top dead center, leaving the diaphragm 11 as it is. Thereby, the gas cooled in the expansion chamber A is sent back into the expansion chamber B while cooling the regenerator 22. This completes one cycle. When such a cycle is repeated intermittently, the cold head 32a reaches an extremely low temperature, and the sensors and the like housed in the vacuum insulation container 4 are effectively cooled.

However, with such a configuration, since the vacuum insulation container 4 has been conventionally used to seal the cold head 32a, the provision of the compressor 1 will improve the overall refrigeration system. The increase in space given to
Only the thickness dimension corresponds to the motor case 33 below the base 31. Moreover, the displacer 21 and the like are also accommodated in the motor case 33, and the compressor 1 is integrated with a part of the expander 2, so the volume actually occupied only by the compressor 1 is is not this large. Therefore, in this case, the diaphragm 11 having a diameter approximately corresponding to the size of the existing vacuum insulation container 4 is simply attached to the base 31, and there is no need to separately secure a completely new space. This makes it possible to realize a configuration that is certainly more compact than a conventional Stirling cycle refrigeration system using a piston, and this is clearer from the diagram.

Moreover, since the operating direction of the diaphragm 11 is made to match that of the displacer 21, it is possible to integrate both drive mechanisms around the movable bracket 51 in a mechanical manner, and this point is also achieved. This is a major factor in the compact structure of the refrigeration system of this embodiment.

Although the operating stroke of the diaphragm 11 is small, since the diaphragm 11 has a large diameter corresponding to the area of the base 31, the compression chamber B with a required volume can be
is sufficiently secured. Therefore, even though this device is compact, it is equipped with appropriate functions.

As described above, a compressor for a Stirling cycle refrigeration system that suitably employs a diaphragm and that does not cause the problem of gas leakage is realized.

Note that a diaphragm without a hole in the center as shown in FIG. 2 can also be used.

In the case shown in the figure, the diaphragm 111 is connected to the base outer wall 1.
31a is substantially completely covered, and the displacer 121 hardly penetrates into the motor case side. A coil 153 for driving the displacer 121 is disposed on the inner periphery of the cylinder 132, and the motor case only houses a drive mechanism consisting of the movable bracket 151 and the coil 152. This configuration does not have a space equivalent to the gas reservoir chamber C in the above embodiment, so it is necessary to drive the displacer 121 and the diaphragm 111 simultaneously during gas transfer, but it has better airtightness and compressibility compared to the above embodiment. Since the volume of the chamber can be secured more effectively, there is a possibility that the -layer can be made more compact. Of course, it goes without saying that the proper operation and effect as a compressor can be obtained in the same manner as in the above embodiment.

Moreover, the drive mechanism may be configured to perform reciprocating motion via a crank instead of using a coil.

Furthermore, it is also effective to configure a water jacket on the base instead of the cooling water pipe to enhance the cooling effect, and various other modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] With the above configuration, the present invention can provide a compressor for a Stirling cycle refrigeration system that is compact and fundamentally solves the problem of gas leakage by suitably employing a diaphragm.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing one embodiment of the present invention, and FIG. 2 is a side sectional view corresponding to FIG. 1 showing another embodiment. 3...Casing 4...Vacuum insulation container 11.111...Diaphragm 21.121...Displacer 31...Base 31 a s 131 a...Base outer wall 32a...
・Cold head B, D...compression chamber

Claims (1)

[Claims] Applicable to a Stirling cycle refrigeration system in which a cold head of a casing containing a displacer is sealed in a vacuum insulated container attached to the base of the casing, the displacer and the operating direction being aligned on the outer wall of the base. A compressor for a Stirling cycle refrigeration system, characterized in that a diaphragm is attached, and an expandable and contractible space formed between the diaphragm and the outer wall of the base serves as a compression chamber.